Attachment for propellers



Oct. 28, 1941. R. F. MUI -ILEb IBRU CK 2,260,736

ATTACHMENT FOR PROPELLERS Filed May 28, 1940 2 Sheets-Sheet l Y .111 ventor w Z'M ufikn break gum A tfomcy Oct. 28, 1941. MUHLENBRUcK 2,260,786

A'rmcmmu'r FOR PROPELLERS Filed May 28, 1940 2 Sheets-Sheet 2 Inventor wfkfzzk Zenrack 4/ A iiomey Patented Oct. 1941 UNITED STATES PATIENT OFFICE" s'rmcmvmnr FOR raornrnuus I Roy F. Muhlenbruck, Hampton, Iowa Application May 28,1940, Serial No. 337,106

; 1 Claim. (01. 11-10-459) 1 This invention relates to an attachment for propellers and is especially adapted for use on aeroplane propellers and similar devices, and has for its primary object the provision of means for reducing to a minimum, if not completely destroying, the resistance of air built up at the hub of "a propeller by the development of a partial vacuum and the dispersing of the compacted body of airin a radial direction and into the path of the propeller blades, whereby the bite of the blades in the air will be materially increased with slippa e reduced to a minimum.

With these and other objects in view, as will become more apparent as the description pr-' ceeds, the invention consists in certain novel features of construction, combination and arrangementof parts as will be hereinafter more fully described and claimed.

Fora complete understanding of my invention,

' reference is to be had 'to the following description and accompanying drawings, in which Figure 1 is a front elevation illustrating a propeller equipped with an attachment constructed in accordance with myinvention.

Figure 2 is a side elevation, partly in section, illustrating the attachment.

Figure 3 is a rear elevation illustrating the attachment.

Figure 4 is a front elevation illustrating a modified form of the present invention.

Figure 5 is a front elevation illustrating another modified form of this invention.

Figure 6 is a sectional view illustrating the form of the invention shown in Figure 5.

Figure 7 is a sectional view taken onthe line ll of Figure 5.

Referring in detail to the drawings, the numeral 5 indicates as an entirety a conventional type of propeller employed upon an'aeroplane or like device including blades 6 and ahub. It is a well known fact that when the propeller 5- is rotated at a high rate of speed a compacted body of air is built up immediately in front of the hub, which compacted body of air oflers a very material resistance to the forward movement of the aeroplane. To reduce this compacted body of air immediately in front of the hub of the propeller to a minimum, the present invention is secured to the front face of the hub and con- .sists of a flat attaching plate 1 provided with openings 8 to receive securing bolts on the hub of the propellerwhereby the plate I is-firmly anchored in place. It is preferable that the plate 1 be of circular formation and formed on its shaped member 9 having the apex thereof disposed forwardly of the propeller.

It is preferable that the member 9 be of hollow formation and openoutwardly through an opening I 0 provided inthe attaching plate so that the usual propeller shaft and securing means of the propeller on the shaft can be received within the memberl.

Radially arranged fins II are formed on the member 9 and coact with the latter in having an angering effect on theair compacted in front of the hub so that this air' will be dispersed in a radial direction and within the path of the blades 6 of the propeller to permit the blades to increase their bite in the air. The compacted body of air being dispersed as specified reduces theresistance and increases the traction of the propeller in the air.

The augering effect of the attachment in the air develops at the hub a partialvacuum, consequently reducing air resistance at the hub to a minimum.

The fins H are curved and dished, as clearly shown in Figures 1 and 3 and extend beyond the periphery of the attaching disc and taper towards their free ends. The butt or attaching ends of the fins are of a width greater than the length of the cone-shaped member 9 so that the butt or attaching ends project beyond the apex of the cone-shaped member and are joined with each other, as indicated at A. The fins constructed as specified will have an augering effect on the air and disperse the. air in a radial direction within the path of the blades of the propeller.

Referring to my modified form of the invention, asshown in Figure-4, the attachment includes the attaching plate l2 and cone-shaped member l3, both of which are constructed similar to the attaching plate I and the cone-shaped member 9.. vIn this modified form of the invention the fins are indicated by the character It.

It is to be noted that thefins I are not curved 3 shown in Figure 5. Struck from the attaching plate [5 is a series of fins or lips l8 certain of .front face and concentrically thereof is a 00119- which extend forwardly of the attaching plate l5 while the others extend rearwardly. Where the lips 18 are struck from the attaching plate openings I! are provided which permita certain amount of air to pass through the attaching plate for cooling purposes. It will be seen that the openings 18 act as vents to discharge part.

of the air immediately back of the propeller hub which air may be used for cooling the engine or other parts associated with the propeller and propeller shaft.

more eflicient traction of the propeller in the air. 7

While I have shown and described the preferred embodiment of my invention, it will be understood that minor changes in construction,

combination and arrangement of parts may be made without departing from the spirit and scope of the invention as claimed.

Having thus described the invention, what I claim is: V

In an attachment for propellers, a circular shaped plate having openings to receive fasteners for securing said plate on the front face of the hub of a propeller and provided with a central opening aligning with the axis of the hub, a hollow cone member formed on said plate over said central opening and having the apex thereof positioned forwardly and axially of the propeller, and a plurality of radially grouped fins including butt ends secured on the cone member and the plate and of a width to project beyond the apex of the cone member and secured to each other at the apex, said plate having struckout portions providing openings therein and lips with some of said lips inclining away from the front face of said plate and the other lips inclining away from the rear face of said plate.

I ROY F. MUHLENBRUCK. 

